A conventional shutter apparatus for the image interception is disclosed, for example, in Patent Document 1. FIG. 18 shows a perspective view illustrating a structure of the conventional shutter apparatus for the image interception.
Conventionally, a shutter apparatus 101 used for a projection display apparatus for the image interception uses a DMD (Digital Micromirror Device: registered trademark) or a liquid crystal display (LCD) panel as a light bulb. Also, the shutter apparatus 101 is used for the projection display apparatus that projects on a screen using a projection lens and is equipped to prevent a light leak in an image mute state. Furthermore, the shutter apparatus 101 is composed of a rotary driving device 102, a shading plate 103 and position detecting sensors 104 and 105. Here, the rotary driving device 102 includes a DC motor, the shading plate 103 is mounted on an output shaft of the rotary driving device 102 and the position detecting sensors 104 and 105 detect the position of the shading plate 103.
Next, the operation (movement) of the shutter apparatus 101 is described. When an image mute is instructed, the rotary driving device 102 rotates the shading plate 103 in an arrow V direction. Then the position detecting sensor 104 detects that the shading plate 103 has moved to the position that completely intercepts an optical path between the light bulb and the projection lens. Then the rotary driving device 102 is stopped.
On the other hand, when the image mute state is released, the rotary driving device 102 rotates the shading plate 103 in an arrow W direction. Then the position detecting sensor 105 detects that the shading plate 103 has moved to the position that is completely away from the optical path between the light bulb and the projection lens. Then the rotary driving device 102 is stopped.
Also, FIG. 19 shows a perspective view illustrating a structure of a conventional shutter apparatus for the aperture adjustment.
Conventionally, the shutter apparatus 111 used for the projection display apparatus for the aperture adjustment uses the DMD and liquid crystal display panel as the light bulb. Also, the shutter apparatus 111 is used for the projection display apparatus that projects on the screen using the projection lens. Furthermore, the shutter apparatus 111 is composed of a shading plate 112, a rotary driving device 113 and position detecting sensors 114 and 115. Here, the shading plate 112 is provided within an illumination optical device in order to enhance a contrast ratio of the image. The rotary driving device 113 includes the DC motor that drives the shading plate 112. The position detecting sensors 114 and 115 detect the position of the rotary driving device 113.
Next, the operation of the shutter apparatus 111 is described. When a high contrast state is instructed, the rotary driving device 113 rotates the shading plate 112 in an arrow X direction. Then the position detecting sensor 114 detects that the shading plate 112 has moved to the position that intercepts a particular part of the optical path within the illumination optical device. Then the rotary driving device 113 is stopped.
On the other hand, when the high contrast state is released, the rotary driving device 113 rotates the shading plate 112 in an arrow Y direction. Then the position detecting sensor 115 detects that the shading plate 112 has moved to the position that is completely away from the optical path within the illumination optical device. Then the rotary driving device 113 is stopped.    Patent Document 1: Laid-Open Patent Publication No. 2001-174910